News tagged with isotopes

In the summer months, phosphorous cycling leads the center of the Chesapeake Bay to suffer from bottom water hypoxia—low levels of oxygen—which makes it hard for oxygen dependent organisms to survive. ...

(Phys.org)—A team of physicists affiliated with institutions in Australia, Switzerland and Austria has made the most accurate measurement to date of the half life of iron-60. In their paper published in ...

From the beginning of time, uranium has been part of the Earth and, thanks to its long-lived radioactivity, it has proven ideal to date geological processes and deduce Earth's evolution. Natural uranium consists ...

University of British Columbia scientists have shown that small cyclotrons – particle accelerators the size of an SUV – can replace hulking nuclear power plants as the country's main source of medical ...

A new analysis of a Martian rock that meteorite hunters plucked from an Antarctic ice field 30 years ago this month reveals a record of the planet's climate billions of years ago, back when water likely washed ...

A study of tooth enamel in mammals living today in the equatorial forest of Gabon could ultimately shed light on the diet of long extinct animals, according to new research from the University of Bristol.

New research published today in the journal Physical Review Letters describes how recreating isotopes that occur when a star explodes, can help physicists understand where life-supporting elements may be found in space.

Isotopes are atoms of the same element that have the same number of protons but a different number of neutrons. Because of the resulting differences in mass ratios, isotope effects can significantly influence ...

Roman gladiators ate a mostly vegetarian diet and drank ashes after training as a tonic. These are the findings of anthropological investigations carried out on bones of warriors found during excavations ...

The use of ringing recoveries —a conventional method used to study bird migration— in combination with more modern techniques such as species distribution modelling and stable isotope analysis helps to ...

The ocean is often depicted as teeming with life, from crustaceans and fish to whales and other mammals, but in fact large swaths of it are virtual deserts, populated only by bacteria and a handful of particularly ...

A recent study of the global carbon cycle offers a new perspective of Earth's climate records through time. Scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science suggest that one of ...

Isotope

Isotopes (Greek isos = "equal", tópos = "site, place") are any of the different types of atoms (nuclides) of the same chemical element, each having a different atomic mass (mass number). Isotopes of an element have nuclei with the same number of protons (the same atomic number) but different numbers of neutrons. Therefore, isotopes of the same element have different mass numbers (number of nucleons).

A nuclide is any particular atomic nucleus with a specific atomic number Z and mass number A; it is equivalently an atomic nucleus with a specific number of protons and neutrons. Collectively, all the isotopes of all the elements form the set of nuclides. The distinction between the terms isotope and nuclide has somewhat blurred, and they are often used interchangeably. If they are to be distinguished in use, isotope is better used in its original sense, when referring to several different nuclides of the same chemical element. Nuclide is a later and more generic term, and is used when referencing to only one type of nucleus, and may also be used to refer to several types of nuclei of different elements. For example, it is better to say that an element such as fluorine consists of one stable nuclide rather than that it has one stable isotope, because the latter word is usually reserved to refer to more than one nuclide. On the other hand, carbon can be correctly said to have two stable isotopes, and fluorine to have several radioactive isotopes.

Isotopes and nuclides are specified by the name of the particular element, implicitly giving the atomic number, followed by a hyphen and the mass number (e.g. helium-3, carbon-12, carbon-13, iodine-131 and uranium-238). In symbolic form, the number of nucleons is denoted as a superscripted prefix to the chemical symbol (e.g. 3He, 12C, 13C, 131I and 238U).

About 339 nuclides occur naturally on Earth, of which 256 (about 75%) are stable (or, to be careful, have never been observed to decay; this note is necessary because many "stable" isotopes are predicted to be radioactive with very long half-lives). Counting the radioactive nuclides not found in nature that have been created artificially, more than 3100 nuclides are currently known.